The angle ABE is opposite the angle CBE and therefore, they are equal; hence,
ABE = 50°
The angle ABC and CBE are supplementary, meaning they add up to 180; therefore,
ABC + 50° = 180°
subtracting 50° from both sides gives
ABC = 120°
The angle EBD is opposite the angle ABC and therefore, they are equal; hence, we have
EBD = ABC = 120°
EBD = 120°
To summarize, our answers are
a. ABC = 120°
b. ABE = 50°
c. EBD = 120°